In winter, it is common to feel bloated and experience discomfort due to irregular bowel movements. Recently, constipation has emerged as a significant health issue. According to statistics from the National Health Insurance Service, the number of patients visiting hospitals for constipation has exceeded 660,000 annually (as of 2019). Particularly, among those aged 65 and older, one in three suffers from chronic constipation.
The first food that those suffering from constipation turn to is undoubtedly sweet potatoes. In a previous survey conducted by a health portal in Korea with 1,121 adults, about 40% of respondents reported consuming fiber-rich foods, including sweet potatoes, to resolve constipation. However, if symptoms do not improve despite sufficient intake of sweet potatoes, it is necessary to closely examine the usual diet.
Recently, a research team from Harvard University confirmed through a large-scale study that the solution to chronic constipation lies not in the intake of specific nutrients but in overall dietary patterns. The results of this study (Dietary Patterns and Incident Chronic Constipation in Three Prospective Cohorts of Middle- and Older-Aged Adults) were published in the December 2025 issue of the international journal 《Gastroenterology》.
The research team tracked and analyzed dietary data over four years from 95,917 adults. The results indicated that the risk of developing constipation significantly varies depending on the dietary patterns maintained.
First, the Mediterranean diet (aMED) and plant-based diet (PDI) were confirmed to have preventive effects against constipation. Groups maintaining a Mediterranean diet rich in fresh vegetables, fruits, nuts, and fish had a 16% lower risk of constipation compared to those who did not. Similarly, groups following a plant-based diet rich in healthy fats had a 20% lower risk of constipation. In contrast, groups adhering to a Western diet high in processed meats and refined grains had a 22% higher risk of constipation, while those following a diet that induces intestinal inflammation (Empirical Dietary Inflammatory Pattern, EDIP) had a 24% higher risk of constipation.
The EDIP utilized by the research team is a dietary pattern that scores foods that elevate inflammatory markers in the body. The higher the related markers, the more they induce microbial imbalance and micro-inflammation in the intestines, hindering peristalsis and increasing the risk of chronic constipation by up to 24%. This diet includes processed meats, refined grains, red meat, organ meats, and high-calorie beverages like carbonated drinks.
It is noteworthy that these results appeared independently of the total fiber intake. In other words, even if you consume a lot of sweet potatoes to meet the recommended fiber intake, if your usual diet is centered around processed foods and red meat, the preventive effects against constipation will inevitably drop.
Many people understand constipation as simply a result of insufficient fiber, but the inflammatory environment in the intestines is also very important. Diets high in processed meats or refined carbohydrates alter the intestinal microbial ecosystem and cause micro-inflammation. This inflammation significantly slows down the speed of intestinal peristalsis. Efforts to supplement fiber are important.
However, it is much more crucial to exclude inflammatory foods that hinder intestinal function from the diet. The Harvard research team demonstrated that the structural harmony of the diet, rather than the fiber content, is the key mechanism for maintaining intestinal function. This means that relying solely on fiber-rich foods like sweet potatoes may not significantly alleviate constipation symptoms.
Applying the Western Mediterranean diet to our table results in a Korean-style Mediterranean diet that aids bowel movement. Here’s how to adapt the dietary elements recommended by the Harvard research team to a Korean table. First, reduce refined carbohydrates. Refined grains, a risk factor in Western diets, are similar to white rice in our meals. Simply replacing white rice with mixed grain rice containing brown rice, oats, and barley can greatly help reduce the risk of constipation.
Second, achieve harmony with vegetable side dishes and plant-based oils. Instead of olive oil from the Mediterranean diet, you can use perilla oil or sesame oil. The habit of mixing seasonal vegetables with fresh oil is good for protecting the intestinal mucosa and aiding peristalsis.
Sweet potatoes, which Koreans enjoy, also have varying effects depending on the accompanying foods. According to the principles presented by the Harvard research team, foods that can further enhance the constipation-preventive effects of sweet potatoes are healthy plant-based fats and fermented foods. Consuming sweet potatoes with perilla oil-dressed vegetables or fermented vegetables like dongchimi can create a synergistic effect.
The dietary fiber in sweet potatoes acts as a prebiotic, feeding beneficial bacteria in the intestines, while the beneficial bacteria in fermented foods improve the intestinal environment. Conversely, eating processed meats like bacon and ham while consuming sweet potatoes can induce inflammation in the intestines, hindering the constipation-preventive effects of sweet potatoes.
In Korea, more than 600,000 patients visit hospitals annually for constipation. What these patients urgently need is not specific foods like sweet potatoes. A complete overhaul of their eating patterns is necessary. Especially older individuals suffering from constipation should quickly increase their intake of plant-based foods and reduce processed foods. Young women who eat irregularly due to dieting and enjoy stimulating delivery foods should also take similar measures.
It is important to remember that the intestines respond not to specific foods but to the daily repetitive eating patterns. It is advisable to replace white rice with mixed grain rice and sausages with tofu and fish. It is also preferable to serve steamed sweet potatoes with vegetable side dishes. Let’s try to resolve the difficulties in bowel movements as quickly as possible with the 'Korean-style Mediterranean diet' that aids intestinal movement.
◇Checklist for Intestinal Health to Prevent Constipation
The following is a checklist based on the dietary patterns that increase the risk of constipation identified by the Harvard research team. Check your usual eating habits. If you meet three or more criteria, you are likely maintaining a dietary pattern that induces intestinal inflammation and increases the risk of constipation.
(1) You consume processed meats like ham, sausage, and bacon more than three times a week.
(2) Your meals are primarily based on refined carbohydrates like white rice, bread, and noodles.
(3) You do not regularly include fresh vegetables or vegetable side dishes in every meal.
(4) You hardly consume plant-based fats like perilla oil, sesame oil, and nuts.
(5) You prefer delivery food or ultra-processed foods over home-cooked meals.
[Frequently Asked Questions]
Q1. What is the reason for not improving constipation even though I consistently eat sweet potatoes?
A1. Sweet potatoes are excellent food, but if other foods you usually eat are causing intestinal inflammation, it is difficult to see effects from just sweet potatoes. According to Harvard's research, maintaining a Western diet with processed meats or white bread increases the risk of constipation by 24%. In other words, it is more important to reduce foods that impair intestinal function (like ham, sausage, sugary drinks, etc.) than to add sweet potatoes.
Q2. How can I practice the 'Korean-style Mediterranean diet' in my daily life?
A2. You can use perilla oil or sesame oil instead of Western olive oil, and various vegetables and mixed grains instead of nuts. Simply replacing white rice with brown rice or oat rice and mixing vegetables with fresh oil in every meal is sufficient. Additionally, filling your protein needs with tofu, beans, and fish instead of red meat will greatly benefit intestinal health.
Q3. What is the first food to eliminate from the table to prevent constipation?
A3. The foods that significantly increase the risk of constipation, according to Harvard's research, are processed meats (like bacon, sausage, ham) and refined carbohydrates (like white bread, sugary cereals). These foods worsen the intestinal environment and dull peristalsis. If constipation is severe, it is recommended to start by reducing the intake of delivery food or processed foods to below 50%.
